1. Field of the Invention
This invention relates to new phosphonic acid ester derivatives and, more particularly, to new phenylthionophoshonic acid O,O-di-esters having a high insecticidal activity, high miticidal activity and high nematocidal activity in combination. This invention also relates to a process for the production of these new phosphonic acid ester derivatives, as well as to an insecticidal, miticidal and nematocidal composition containing the above-mentioned new compound as active ingredient.
2. Description of the Prior Art
Many kinds of organo-phosphorus compounds having insecticidal activity, miticidal activity and/or nematocidal activity are known. Thus, O-(N-alkoxy-benzimidoyl)-(thiono)-phosphoric(phosphonic)acid esters having insecticidal and miticidal activities are disclosed in Japanese patent application prepublication "Kokai" No. Sho 47-9149 (corresponding to U.S. Pat. No. 3,760,041), Japanese patent application prepublication "Kokai" No. Sho 49-13335 (corresponding to U.S. Pat. No. 3,872,185) and Japanese patent application prepublications "Kokai" No. Sho 49-132244 and No. Sho 50-64436. O-(N-Alkoxy-substituted alkylimidoyl)-(thiono)phsphoric acid esters are also known to have insecticidal and miticidal activities as disclosed in Japanese patent application prepublications "Kokai" No. Sho 50-6724 and No. Sho 52-33627.
Amongst the insect pests, rice stem borer, brown planthoppers, rice leafhoppers, common cutworms and aphids may be mentioned as the main insect pests which are predominantly infesting aquatic rice plants cultivated in the submerged field or the crops cultivated in upland fields in recent years. For the purpose of combating these main insect pests, there have been applied large quantities of insecticides of the organo-phosphorus compound type, insecticides of the carbamate compound type, insecticides of the chlorinated compound type and others since a long time ago. In these years, there occurs an objectionable phenomena that the main insect pests have gained a resistance against the known insecticidal compounds which have extensively been used in the crop fields.